Furnace



April 28, 1925.

C. J. WRIGHT FURNACE Filed May 6. 1921 3 Sheets-Sheet 1 April 28, 1925. Y 1,535,277

c. J. WRIGHT FURNACE e5 med may', v1921 s sheets-sheet 2 I l, .-r 4Z as@ 42 43 April 2s, 1.925. 1,535,277

Patented Apr. 28, 1925.

`UNrrED STATES PATENT OFFICE.

CARL J'. WRIGHT, OF TOLEDO, OH'IO, ASSIGNOR T BOHERTY RESEARCH COMPANY, OF

NEW YORK, N. Y., A CORPORATION F DELAWARE.

FURNACE.

Application led May 6,

To @ZZ whom @'15 may concern.'

Be itlrnown that l', CARL J. lViuonT, a citizen of the United States of America, residing at Toledo, inthe county .of Lucas',

State of Ohio, have invented certain new and useful Improvements in Furnaces; and I` do `hereby declare the following to be a full, clear, and exact description of the in-V vention, such as will enable others skilled in the art to which it appertains to make and `use the same.

This invention relates to furnaces and particularly to furnaces which may be vused for melting brass or other non-ferrous metals in crucibles Heretofore, so far as applicant is aware, furnaces for melting brass in crucibles have always been heated by coke or anthracite coal, since the temperature requiredl to heat the crucibles tothe requisite degree could not be obtained by the use of other fuels. F or example, crucible furnacesas formerly constructed were not adapted to develop a sufficiently high temperature from gaseous fuel to properly melt brass in crucibles.

It is an object of this invention to provide a furnace in which gaseous fuel maybe em-` ployed to heat a crucible in order to melt brass orto perform other metallurgical operations for which Crucible furnaces are commonly employed. To this end animportant feature of the invention resides in the provision of a chamber constructed to contain a crucible and having regenerator chambers associated with it for pre-heating the air which is used to support the combus tion of the fuel in the furnace. In the illustrated apparatus, the crucible chamber com prises `a series of compartments each constructed to contain a crucible `and is formed by walls projecting inwardly from the oppositeends of the furnace and spaced from the sides of the furnace to provide a regenerator chamber on'each side of the crucible chamber. The regenerator chambers are connected with opposite ends of the crucible chamber by passages into which `gas is introduced by burners seated lin the walls of the furnace.

In accordance with a further feature of the invention the furnace is equipped with means for removing a crucible from it. As shown, such means comprises a hydraulic elevator associated with each of the compartments of the Crucible chamber and de- 1921. Serial No. 467,250.

tion of the elevators.

In the operation of regenerative furnaces, the rcgenerator chambers arel alternately heated by the exhaust gases leaving the fur nace and cooled by the air which is introduced into the furnace to support the combustion of the fuel. l/Vhen the valve for vices for separately controllingl the opera controlling the air andexhaustgases has` the exhaust gases to the regenerator def creases until a. point is reached where the heat transferred to the regenerator in any given interval of Y time is less than Vthe amount required to heat the quantity of air which is supplied to the furnace during such interval. efficiency from the regenerators, it is neces sary to reverse the controlling valve before Vthe above-inentioned point isreached.

If, on the other hand, the controlling valve of a` regenerative furnace is reversed when too small amounts of exhaust gases have been passed through the regenerators, they will be insufficiently heated. The temperature of the furnace will, consequently, be low, since it depends `in great measure on the degree to which the air is pre-heated inv the regenerators. Nhenthe periods between l reversals are short a further loss of efficiency is suffered by reason ofthe time` consumed in effecting them. y Y A lt is a further objectof the invention to provide valve reversing mechanism for regenerative furnaces which will enable the regenerators to be utilized always at their highest efficiency. To this end another important feature of the invention resides in the provision of means for controlling the speed of the operating means for the valve reversing mechanism and, consequently, the intervals of time between the operations of the valvereversing mechanism, in` accordance with the rate of supply of fuel to the In order to obtain the maximum Y furnace. rlhe illustrated construction is such that when the rate of supply of fuel to the furnace is increased or decreased, the speed of operation of the valve reversing mechanism is also increased or decreased to shorten or lengthen, as the case may be, the intervals of time between the reversals of the furnace controlling valve. The means for controlling the rate of supply of fuel to the furnace is so connected with the operating means for the valve reversing mechanism that the intervals of time between the operations of the furnace controlling 'valve are made shorter or longer in accordance as the rate of supply of fuel to the furnace is increased or decreased, in such a ratio that, regardless of variations in the rate of supply of fuel to the furnace, the reversals of the iow of a'f and exhaust gases through the regenerator chambers take place when the temperature of the regenerator chambers is substantially that at which they operate with the maximum eficiency.

A further feature of the invention contemplates the use of an electric motor for operating the valve ,reversing mechanism, a valve for controlling the rate of supply of fuel to the furnace, and a. rheostat associated with the valve and arranged to interpose more or less resistance in the motor circuit in accordance as the valve is moved toward closed or fully opened position.

Other objects and features of the invention will appear as the description proceeds and will be pointed out in the appended claims.

In the drawings which illustrate a preferred embodiment of the invention;

Fig. 1 is a View in plan of a crucible furnace and valve mechanism for reversing the flow of air and exhaust gases through it, the furnace being shown in section;

Fig. 2 is a longitudinal sectional elevation of the furnace taken substantially on the line 2-2 of Fig. 1;

Fig'. 3 is a transverse sectional elevation of the furnace taken substantially on the line 3 3 of Fig. 2;

Fig. l is a view of the valve reversing mechanism in side elevation;

l Fig. 5 is an elevation of the valve reversing mechanism taken on the line 5 5 of F Ll.

Fig. 6 is a view similar to Fig. et., but showing the cam members of the valve reversing mechanism as having been rotated through nearly 180D from the positions occupied by them in Fig. 4; and,

Fig. 7 is a detail view of the rear valve reversing` devices showing' them in the positions which they occupy just subsequent to the reversal of the valves.

The illustrated construction comprises a furnace 1l) supported by walls 12. The floor 14 of the furnace is upheld between the walls l2 by double angle irons 16 which have their ends seated in the walls 12 and their central portions supported on a wall 18 which is disposed longitudinally of and beneath the furnace l0.

Manifestly, the furnace may be made in various forms. As shown, however, the outer wall 2O of the furnace is rectangular in shape and is lined with layers 22 and of refractory material. Projecting inwardlj,v from the end walls of the furnace 1() are wa ls 26 and 28 spaced from the side walls of the furnace to provide regenerator chambers 30 and 32 which if desired may be filled with the usual loosely piled tire brick or other suitable heat storage elements. The projecting ends 34 and 36 of the walls 2li and 28 are also spaced from the end w lls of the furnace so as to leave passages 38 and l0 which connect the regenerator chambers 30 and respectively with the chamber 4t2 intervening between the walls 26 and 2S. ln the illustrated construction, the chamber l2 is of a length su'llieicnt to contain a number of crucibles and is divided by transverse bars est and oppositely disposed meinbers Ll5 extending inwardly from the walls 2G and 28 into live compartments each constructed to contain a single crucible. The compartments of the chamber l2 are provided with covers 46.

The main floor 14 of the furnace is sheuldered at f7 below the walls 26 and 2S to receive blocks 4S constituting the bottom of the conipartnients of the chamber e2. ln the present practice of heating materials in crucibles, it is customary to lower them into and to lift them from the furnace by means of tongs which engage internally shouldered portions near their tops. The cruciblcs are son'letimcs brolttn in the furnace, thus rendering it in'ipossible to renuive them from it by means of the usual tongs. flu such cases it is often very dillicult tor-cmc-ve the crucibles from the furnace. lu order to avoid this objection, the bloc (s -l-l of the present invent-ion are formed with openings .30 tapering downwardly from their upper ends and having seated therein corre-- spondingly shaped heads 52 of vertically disposed elevators 52.

rlhe heads of the elevators are located centrally in the conipartnicnts of the cluunber 42 so as to receive and support the crucibles 43. As shown, the wall 1H of the furnace hollowed out at a8 to receive the elevators 511, and arranged verlically in the cavitie' 58 are rails or the like ti() on which ride rolls (S2- carried by the elevators 54. In order to enable the clevators 5a to be raised to lift the crucihles from the f-.n'nace.I the elevators are fori'ned with depending stems on which are piston heads 6G received in cylinders G8 mounted in the wall 18. Tl. Cylinders are prov sure pipe 74 and an exhaust pipe 7G by valves 78. From the foregoing it will be understood that the elevators 54 may be independently operated by actuation of the Valves 78.

The blocks 48 forming the botto-m o-f the crucible compartn'ients are placed in contact with each other and are cemented together to form a floor common to all of the compartments of the chamber 42.

rlhe floor f the chamber 42 is grooved adjacent to the walls 26 and 28 `to form troughs 80 on opposite sides of the'chamber.

The troughs 80 collect any slag' which for any reason such for'exannlalmas the breakage of a Crucible may be spilled in the crucible chamber and discharge it from the furnace through openings 82 communicating with suitable eduction conduits (not shown).

VAs already indicated vthe furnace is particularly adapted to burn gaseous fuel. ln the illustrated construction, gas of suitable character, for example, water gas, is introduced into `the 'furnace through burners 84 and 8G located in the ends of the furnace in line with the chamber 42. 1t will be apparent, therefore, that gas introduced into `the furnace through burners 84 and 86 first enters the passages 40 and 38 where it `mingles with air from the regenerator chambers 82 and 30 respectively. Two of `the burners 84 and 8G are preferably seated the passages 88 and 40 by pipes 90 and 98' respectively. rllhe pipes 96 and 98 are in turn connected with a valve casing 100 containing a four-way valve adapted to admit Y air selectively to the regenerator chambers and 32. The air and gas control valves are connected to shaft 102 for operation thereby, the arrangement ofthe valves being such that during certain of the a tei-nating periods of operation of the' furnace, gas and air are introduced into the furnace through the burners 84 and pipe 98 respectively, whereas. duringl the other periods gas and air are introduced into trie furnace Y through the burners 80 and pipe 96 respectively. -ln the former Yperiods the air is pre-heated in passing through the regenerz tor chamber 82 to the passage 40 where it mixes with gas `from the burners V84'. The combustion of the gas takes place mainly in the chamber 42 for which reason the chamber 42 is sometimes referred to hereinafter as a combustion chamber. The members on the walls 26 and 28 direct the burning gas into close contact with the crucibles 48. rl`he `exhaust gases from the combustion chamber 42 pass through the passage 38 into the regenerator chamber 30 and thence through the pipe 96 Vto the valve casing 100 from which they issue through a pipe 104. During theV intermediate per iods of the operation of the furnace, air enters the regene-rator chamber 30 through the pipe 90, and, after being predicated in that chamber, mingles in the passage 38 with gas entering the furnace through the burners 86. The gas is then burned in the combustion chamber 42, and the exhaust gases pass from the chamber through the passage 40 and the regenerator chamber 32 to the pipe 98 whichV conducts them to the valve casing 100 and pipe 104. y

The valve operating shaft 102 is oscillated so as alternately to reverse the valves in the y casings 92 and 100 in` order to cause gas and air to enter the furnace during alternate periods through the pipes 844-98 and the pipes`86-96- It is essential that the valves be reversed at regular periods, and it is very desirable that the movement of the `valves fromV one position to another, when once initiated, 'shallbe quickly effected.

In the preferred embodiment of the invention', the shaft 102 is journaled for oscillation in a frame 100 Vadjacent to the furnace 10, and the reversal of the valves is accomplished quickly and at regular intervals by mechanism including arms 108 and 110 (Figs. 4 and 6) fast on the shaft. As shown,

`the'arms 108 and 110 extend downwardly extending from one end of the frame 100 to the other. Aspring 120, attached at one end to an ear 122 (Figs. 4 and 6)',on the -device 112 and at its other end to a suitable anchor 124 carried by the framex106 urges the device toward the arm 108.

Co-acting with the arm 110 is an actuating device 126 (Figs. 4 and 7), the upper por? tion of which is constituted by ar bar 128 carrying a pin 130 at its free endin position to engage the arn'i 110. The device 126 mounted for sliding movement on a bar supported horizontally on the frame 106 in like manner to the bar 118. .4. spring 184 suitably secured to the device 126 and the fran'ie 106 urges the device toward the arm 110.

The devices 112 and 126 are disposed respectively below and above the horizontal plane through tbe axis of the shaft 102 and are mounted for movement parallel to that plane. The devices are controlled in their operations ou the arms 108 and 110 by mechanism including` a sleeve 136 loosely mounted on the shaft 102 and carrying cams 168 and 140 arranged to engage rolls 142 and 144 on the devices 112 and 126 respectively. rlfhe sleeve 186 and the cams 138 and 140 may be rotated by a worm wheel 146 fixed to the sleeve. Meshing with the worm wheel 146 is a worm 148 on a shaft 150 journaled in the frame 106. The shaft 150 is in turn provided with a worm wheel 152 meshing with a worm 154 on a shaft 156 jonrnaled on the frame 106 at right angles to the shaft 150. The shaft 156 is operated by gearing 156 from the shaft 160 of an electric motor 162 suitably mounted on the frame 106.

The cams 1238 and 140 are of like construction and are mounted on the sleeve 1516 at angles of approximately 1800 to each other1 (Figs. 4, 6 and 7). Each of the cams comprises a semi-circular peripheral face 164 of substantially 180o in length, a straight face 166 extending inwardly fiom one end of the peripheral face 164 to a pointadjacent to the shaft 102, and a cam face 168 extending from the peripheral. face 164 to the base of the straight face 166 adjacent to the shaft 102.

rthe valve reversing mechanism operates as follows: The cams 188 and 140 are rotated in the direction of the arrows (Figs. t and 6) and when the edge 170 at the junction of the straight face 166 and peripheral face 164 of the cam 188 is carried past the roll 142 on the device 112, the deiice is moved to the left (Fig. 4) by its spring 120 to cause it to impact sharply on the arm 108, thereby moving the arm 108 quickly to the left (Fig. and oscillating the shaft 102 to reverse the position of the valves. In this position of the parts, the roll 144 on the device 126 engages the peripheral face 164 of the cam 140 and thus causes the device 126 to be maintained in a position such that the pin 180 is held out of the way of the arm 110 as it moves to the right in response to the movement of the arm 108 to the left. In the continued rotation of the cams'188 and 140, the device 112 is moved to the right by the cam face 168 of the cam 188 to the position shown in Fig. 6, it being apparent from Fig. 6 that the vdevice 112 is moved to fully withdrawn position before the edge 172 of the cam 140 passes from the roll 141 on the actuating device 126. Consequently, when the edge 172 of the cam is moved past the roll 144 on the device 126, thus permitting that device to be operated by the spring to engage and actuate the arm 110, the device 112 is held away from the arm 108 to allow unin'ipeded retrograde movement of the arm 108 to the right as the arm 110 moved to the left by the device 126. 1t will be understood, therefore, that the cams 138 and 140 not only control the actuation of the arms 108 and 110 by he dev'ces 112 and 126 respectively, but also that each of such cams by reason of their arrangenient and the provision of each with a semi-circular peripheral face of a length of 1860 operates, following the operation of the device 112 or 126, to move the device out of the way of its co-acting arm 108 or 110 before the next succeeding operation of the other arm. 1t will, furthermore, be apparent, inasmuch as the devices 112 and 126 operate by impact under the action of the sprii 120 andr114 to reverse the valves, tl tt after reverse in vement of the valves is initiated, it is very quickly effected so that the time expended in reversing the valves is reduced to a minimum.

It is in'iportant that the flow of air and gas to the furnace 10 shall be reversed when the temperature of the regenerators is substantially that at which the furnace operates with the maximum efficiency. 1n the illustrated construction, this is effected by varying the speed of operation of the motor 162 in accordance with variations in the rate of supplv of to the furnace. As shown, the rate of supply of gas may be varied by a valve 174 in the main gas supply pipe 94, and connected with the valve 174 is a rheostat 176 interposed in the circuit of the` motor 162. The rheostat 176 controls the speed of operation o-f the motor 162 and inasmuch as the air and gas control valves are reversed at the end of each movement of the cams 1?8 and 140 through an angle of 1800, the rheostat 176 also governs the length of the intervals between the reversals of the valves. The arrangen'ient of the valve 174 and rheostat 176 is such that when the rate of supply of to the furnace is increased or decreased. the intervals of time between the reversals of the valves are made shorter or longer in such a ratio that the temperature of the rcgenerators at the time of the reversals of the valv is caused always to be substantially that at which the regeneratoi's operate with the highest etliciency.

Having described the invention what is claimed is 1. 1n a furnace of the class described, an

elongated combustion cham ier constructed to contain. a plurality of crucibles, means for introducing into the ends of the chamber,

means for pre-heating the air which is used to support combustion in the chamber, means for reversing the flow of air and gas through the combustion chamber, and Ydevices eX- tending inwardly from the walls of the combustion chamber and acting to direct the burning gas into close contact with the crucibles in thechamber.

walls projecting inwardly. from substantially opposite parts of the furnace and arranged to define a. centrally located chamber constructed to contain a crucible, said walls `beingspaced from the adjacent portions of the wall of the furnaceV to provide rcgenerator chambers at` each side of the first-mentioned chamber and each of the first-mentioned walls having its projecting end spaced from-the wall of the furnace to form passages which connect the ends of the central chamber with the regenerator chambers, means for supplying air and fue-l to the furnace, and means for periodically re-Y- versing the flow of air and exhaust gases through the regenerator chambers.

3. In a furnace of the class described, walls projecting inwardly from opposite sides of the furnace and arranged to define an elongated centrally-locatedchamber constructed to contain a series of crucibles, said walls being` spaced .from the other sides of thefurnace to provide regenerator chambers at each side of the central chamber and each of the walls having its projecting end spaced from the wall of the furnace to form passages which connect the ends of the central chamber with the regenerator chambers,

burners arranged to supplylgas to said'passages, means for supplying air to the regenerator chambers, and means for periodically reversing the supply of gas and air to the burners and the regenerator chambersrespectively. v

4. In a furnace ofthe class described, an elongated 'chamber comprising a .plurality of compartments each constructed to contain a Crucible, a movable support located below the central portion of each of the compartments, means for elevating the supports to lift crucibles from the chamber, a floor common to all of the compartments andV formed to provide troughs on opposite sides of the supports, said troughs acting to collect slag which may escape from a crucible in any of the compartments so as to enable the slag to be discharged from the chamber,

v i and means for heating the chamber. 2. In a furnace of the class described,l

5. In a regenerative furnace, valve reversing mechanism, an electric motor for operating said mechanism, a rheostat for controlling the speed of the motor, and means for setting the rheostat in accordance with the rate of supply of fuel to the furnace.

6. In a regenerative furnace, means for supplyingI fluid fuel and air to the furnace, valves for directing the fuel and air selectively to different parts of the furnace, valve reversing mechanism, an electric motor for operating the valve reversing mechanism, a valve for controlling the rate of supply of fuel to the furnace, and means connected with the last-mentioned valve for controlling the speed of the motor in accordance with the rate of supply of fuel to the'furnace.

7. In a regenerative furnace, regenerator chambers, means for controlling the operation of the furnace comprising a valve, valve reversing mechanism, a driving device for operating the valve reversing mechanism,V

means for varying the rate of supply of fuel to the furnace, and means for increasing or decreasing the speed of operation vof the driving device when the rate of supply ofV fuel is increased orv decreased so as to cause the valves to be reversedV after the regenerator chambers -have been heated by the eX- liaust gases substantially to the point of highest eificieiicy.`

8. In a regenerative furnace, valve reversing mechanism, means for operating said mechanism, and means for controlling the speed of 'operation of the operating means in accordance with the rate of supply of fuel to the furnace.

In testimony whereof I affix my signature.

CARL J. wiiieii'i. 

